Method of pickling brass.



UNITED STATES PATENT OFFICE.

RALPH R. PARISH, OF WATER-BURY, CONNECTICUT, ASSIGNOR T0 CHASE ROLLING MILL 00., 0F WATERIBURY, CONNECTICUT, A CORPORATION.

No Drawing.

To all @071 am it may concern:

Be it known that I, RALPH R. PARISH, a citizen of the United States, residing at \Vaterbury, in the county of New Haven and State of Connecticut, have invented a new and useful Improvement in Methods of Pickling Brass; and I do hereby declare the following to be a full, clear, and exact description of the same.

As the art of making rolled or wrought brass has heretofore been practised, acertain pereentage of inferior stock has been produced, owing to the imperfect plckling of the brass after annealing it, due to the fact that the pickling solutions heretofore em ployed have been so far ineffective in their operation that they have left upon the surfaces of the pickled brass some irregular film-like deposits or blotches of pure or relatively pure copper which appear in the finished product in the form of so called stains, which, as the process proceeds, step by step, are rolled into the metal and roduce unsightly and unworkable areas. All such stained sheet brass is classed as inferior stock.

The object of my invention is to avoid these objections by improving brass pickling solutions so that they will be more effective and prevent the appearance upon the brass of any disfiguring films or deposits of pure or relatively pure copper.

Vith these ends in view, my invention consists in a brass pickling solution reinforced by a per acid or a derivative thereof, which dissolves the copper and copper oxids of whatever nature, formed upon the surfaces of the metal during the process of annealing.

My invention further consists in a brass pickling solution and a certain method as will be hereinafter described and pointed out in the claims.

It is well understood in brass mills, that owing to a great variety of causes, superficial deposits of copper or copper oxids or both appear upon the brass during the successive annealing operations. Under perfect conditions of annealing, these objectionable deposits upon the brass do not occur, but they are so liable to occur, and so excessively difficult to control, that it is necessary to provide for removing them when they do occur in order to secure a product entirely of the Specification of Letters Patent.

Application filed January 12, 1914. Serial No. 811,741.

"aid 115 sulfuric acid in Patented Aug. at, 1914.

first grade of rolled brass. Provision is therefore always made in brass mills for pickling the brass immediately after it has been annealed. The pickling solution generally employed consists of a solution of about l .Qf...S. 11 1il1.li i!. i w tc y invention consists in introducing into such a pickling solution, a suflicient amount of a per acid, 011a derivative of a per acid, to

the solution in attacking and dissolving the objectionable surface disfigurements, whatever the character of the same may be. On this point it may be said that a great many factors not necessary to here rehearse vary the amount and character of the disfigurements or blotches, such, for instance, as the composition of the brass itself, the character, condition and mode of operating the annealing furnace used, the character of the fuel employed, the draft of the furnace and so on. In practising my invention, I may employ any suitable per acid or any suitable per acid derivative, such as pers lf ric acid 11,8 0,, per-selenic acid H Se O,, per-chromic acid CrO,H,O or any of the salts derived from such acids. The amount of the per acid or per acid derivative used will be gaged according to the speed at which it is intended the pickling operation shall proceed. I have obtained good results by an amount of per acid or per acid derivative equivalent to about ten per cent. of the sulfuric acid content of the pickling solution.

The per-acids above referred to are what are cheiiiTcTilfi known as true per-acids delined by so eminent an authority as T.

Slater Price in his monograph on Per-Acids and Their Salts, (London 1912) as those which are either formed by the action of hydrogen peroxid on ordinary acids, or else give rise to hydrogen peroxid on treatment with dilute sulfuric acid. To this generalization Price makes but one exception in this language: In the case of persulfuric acid, H 8 0 chlorsulfonic acid has to be used, and not sulfuric acid. I would have it understood that in employing the term peracid in the text and claims of my application, I use it in the sense in which the term is defined as above by Price.

I claiin:

1. A pickling solution for removing disfiguring blotches appearing upon annealed brass, the said solution consisting of a sulfuric acid solution reinforced by a per-acid or a derivative thereof.

2. A pickling solution for removing dis- 5 figuring blotches appearing upon annealed brass, the said solution consisting of a sulfuric acid solution reinforced by a per-sulfuric acid or a derivative thereof.

3. A method of pickling annealed brass 10 consisting in subjecting it to the action of a pickling solution of sulfuric acid which has been reinforced by a per-acid or a derivative thereof.

In testimony whereof, have signed this specification in the presence of tWo subscrib- 15 ing Witnesses.

RALPH R. PARISH. Witnesses:

FREDERIG C. EARLE, CLARA L. WEED.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. 0. 

